package LeetCode;

public class Code141_hasCycle {

    public boolean hasCycle(ListNode head) {
        if (head == null){
            return false;
        }
        ListNode slow = head;
        ListNode fast = head;
        while (fast != null && fast.next != null){
            slow = slow.next;
            fast = fast.next.next;
            if (fast == slow){
                return true;
            }
        }
        return false;
    }
}
